Insecticide formulations



United States Patent INSECTICIDE FORMULATIONS Leo Trademan, Marshall A. Malina, and Louis P. Wilks,

Chicago, IlL, assignors to Velsicol Chemical Corporation, a corporation of Illinois No Drawing. Application November 5, 1954 Serial No. 467,204

4 Claims. (Cl. 167-30) 7 Thisinvention relates to insecticide compositions and to methods of stabilizing them. More particularly, the present invention relates to dry formulations of certain halogenated insecticides stabilized with a combination of sodium hydroxide and organic compounds containing two hydroxyl groups.

Dry formulations of halogenated insecticides fall into three main classifications, namely, dusts, wettable powders, and granular formulations. Dusts and granular formulations differ primarily in particle size of the carrier or diluent used. For example, a typical dust formulation may comprise an insecticide dispersed in a solid carrier having a particle size smaller than about 325 mesh. A typical granular formulation would comprise an insecticide dispersed in a solid pulverulent carrier having a particle size of about 20-80 mesh. A typical wettable powder comprises an insecticide and a solid pulverulent carrier having a particle size of the order of that used for dust formulations, in conjunction with wetting and dispersing agents.

Typically, a granular formulation may contain from about 1% to about 35% insecticide. This type of formulation is generally used as such without further dilution with an insecticidally inert pulverulent carrier in such fields as agriculture.

Typically, a dust formulation can contain about 0.25% insecticide up to about 50% insecticide. Frequently, the dust formulations are first prepared as so-called concentrates which contain typically from about 10% to about 50% insecticide dispersed in the dust and such concentrate is further diluted to a so-called field strengt dust typically having an insecticide concentration of about 0.25 to about 5%, varying with the use desired and the potency of the insect toxicant.

The wettable powders typically contain a concentration of toxicant on the order of that contained in dust concentrates as above described. However, these wettable powders are diluted to field strength by dispersing in water rather than by further dilution with dust.

The toxicant ingredient of the dry insecticide formulations which is stabilized by the present invention is selected from that class of insect toxicants which are derived from hexachlorocyclopentadiene and which are specifically typified by chlordane, heptachlor, aldrin, isodrin, dieldrin, or endrin, either in their pure or technical form.

The carriers or diluents generally used with these insect toxicants, and which in their normal state are active in deteriorating the aforesaid class of toxicants when mixed therewith without treatment as specified in the present invention, are pulverulent solids of the class consisting of kaolin clays, montmorillonite clays, attapulgite clays, diatomaceous earths, and vermiculites.

concerned, the insect toxicants employed, and the carriers and diluents used, a brief discussion of the problem encountered in such formulations will be helpful in understanding the present invention.

While the solid carriers above discussed are very useful in formulating the herein defined toxicants for reasons of their inexpensiveness, availability, ease of handling, absorbency characteristics, durability and other desirable physical properties, they have the disadvantageous property, to varying degrees, of degrading or decomposing the insect toxicant when intimately mixed therewith. While this degrading action is a slow process, it issignificant and troublesomeysince dry formulations are often prepared as concentrates or even field strength materials and then stored for periods which may be as long as a year or more. During this storage period the effect of the carrier or diluent on the insect toxicant may reduce its effectiveness to the point where satisfactory insect control under field conditions is no longer obtainable.

The nature of the reaction or effect of the carriers on the chlorinated insecticide has never been fully elucidated. The rate of toxicant deterioration may vary by the action of dilferent carriers or diluents.

To solve the present problem it has been found necessary to neutralize the activity of the solid carriers and diluents so that they are inert to the insect toxicant and will allow protracted storage of dry insecticide formulations without deterioration of insecticidal activity of such formulation. Since the formulations herein concerned are used preponderantly in agriculture, any treatment of the carriers and diluents used must necessarily not render the formulation unfit for agricultural use on food and forage crops at time of harvest. Thus, the treatment must not render the formulation phytotoxic. The treatment must likewise not be hazardous from a warm-blooded animal toxicity standpoint or otherwise increase the hazard in the utilization of insecticide formulations. Alsoof primary importance, and considering the economics involved, the material should be relatively inexpensive and readily incorporated into dry insecticidal formulations.

As described and claimed in our copending patent application, Serial No. 461,036, filed October 7, 1954, the addition of glycol material selected from the class ethylene glycol, diethylene glycol, propylene glycol, and triethylene glycol to the carriers herein defined has the beneficial effect of alleviating or eliminating degradation or deterioration of the herein defined insect toxicant inl Patented Feb. 24 1%9 hydroxide in theformulations has no adverse efiect on the performance of said insecticidalformulations when" applied under field conditions.

While the glycol material herein defined will effect stabilization of the formulations by itself, sodium hydroxide will, not work by itself.

equivalent stabilization results. Actually, on .a weight basis, .thezcaustic soda can. replace more thanitsweight of glycol without deleterious effect on the stability oflthe; final formulation The benefit of suchv replacement. of. glycol with sodium hydroxide without diminution of beneaficial result is immediately apparent when it is considered that caustic soda costs only a fraction of the glycols de-- fined.

It has'been found that as much as 66% of glycol heretofore used by itself as a stabilizing agent can be replaced with less than an equal weight of sodium hydroxide without loss of effectiveness. Thus, the present invention con templates the use of glycol and caustic soda in a proper: tion'of from about 20% to about 70% of sodium hydroxide to'from about 30% to about 80% of a glycol selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol and triethylene glycol.

Thevglycol and sodium hydroxide additives of the pres-' ent invention have the beneficial effect of alleviating or eliminating degradation or deteriorationof the insects toxicant ingredient in dry insecticide formulatons: when contained in such formulations in combinedamounts varying between about /2% to about 12% by weight based on the weight of carrier or diluent contained in. the formulation. A preferred concentration is about 2% v to about 8% on the same basis.

Specifically exemplifying the benefits of thepresent invention, where- 7% of diethylene glycol was used to achieve. a stable formulation on a particular carrier, it. is,by the practice of the present invention, possible to use as little as 3% diethylene glycol alongwith. 2% I to. 3% sodium hydroxide.

The art of blending materials with solid carriers is well.

Itis thus surprising that sodium hydroxide can be used to replace substantial proportions of. glycol used .as stabilizer whileachieving I known and the additives of the present invention. can be blended with these solid materials by any known means.

Forexamplatheuse of commercial type mixers or .blenders is adequate;

Preferably, the caustic soda is combined with the' glycol material in aqueous solution and .the two-component stabilizer is then added in one operation. Alter-" uatively, these two components can be'added individually in any sequence. When added individually, the glycol component can be added to and blended with the solid carriers either alone or in combination with an inert, relatively volatilev solvent which can .be. removed after blending; The caustic soda ingredient, when added individually, is preferably added as a water solution such as one of about 30% to 40% concentration.

The two-component stabilizer additive can be added to the solid carriers prior to blending the insect toxicant therewith. In theralternative, the glycol additives can be added tothe solid carriersduringthe same .blending operation wherein mixing of the insect ,toxicant .and:.car rier is achieved. It is preferred to preblendLthe twocomponent additive to the carrier before blendiug'the:

insect toxicant.

The stabilizing effect of the glycols herein described,: when used alone, has, already been shownandudiscussed in the aforesaid copending application. The following shows additional data indicating the benefitof the use of caustic soda along with said glycol material:

Table [Amounts expressed in weight percent] Stabilizer Formulation Heptachlor Carrier Diethyleue NaOI-I Glycol 2. 67 10. 7 87.63 (Kaolin). 0. 89 0. 67 10.5 87.94 (Kaolin). 6. 22 11; 2 82.58 (Attapulg'ite). 3. 5G 1. 77 11. 1 83.57 (Attapulgite). 2. 66- 2. G6 11. 1 83.57 (Attapulgite). 4. 5 10.2 85.3 (Diatomaceous arth 1 8 1.35 10 2 86.65 (Diatomaceous Eart . Formulations containingthe components as stated in the above table were subjected to accelerated storage tests in an oven maintained at 122 F. After thirty daysof such? storage the heptachlor content of each 'such formulation-remained unchanged and degradationhad nottaken place." On the other hand, formulations such askB, D. E, -and G, containing an equal level of glycol but without any sodium hydroxide, .are not'stable when subjected to accelerated storage conditions as defined.

While the stability of such formulations as B, D, E; and

G in. the." absence of caustic soda .but in the presence of theindicated level of. glycol is greater than the sameformulations withoutany stabilizer, such formulations containing lower levels of glycol material are not as stable. as the formuiations containing the same low level of .glycol material supplemented by the indicated levels of icaustic.

While .the' glycol indicated in the-table is' diethyleneglycol, the'other glycols, namely,.ethylene glycol, triethyl-J ene':glycol and'propylene glycol are similar in their stabilizingactionboth alone and when used in conjunctionwith caustic soda.

Similarly, while the data in the tablewas accumulated usingheptachlor as-insect toxicant, the other hexachlorocyclopentadiene derivedinsect toxicants are likewise benefited by the treatment of the present invention,

Theabove results show that a glycol-caustic soda combination is as eifective as glycol alone in substantially a eliminatingdecomposition of dry insecticidal formulationsr The use of the caustic soda-glycol combination as stabilizer is unusually economical and represents a reduction of from 45% to about 60%' on the cost of. stabilizationuby glycol alone. I

It is toibenoted that the total amount of glycol-caustic combination necessary to produce stability is somewhat lesswthan the amount of glycol alone and apparentlyis due eithento asynergistic efrect orby adjuvant action of the sodium hydroxide.

We claim: i 1. -A'-stabilizedinsecticidal composition comprising in combination :--an insect toxicant derived from hexachlorocyclopentadiene selected from the group consisting of endrin, isodrin, aldrin, dieldrin, chlordaneand heptachlor;

a finely divided solid carrier active in deteriorating said in-' sect toxicant mixed therewith selected from the group consisting :of kaolin clay, montmorillonite clay, attapulgite clay, diatomaceous earth and vermiculite; and between /2%I:and-l2% by weight. of the carrier of a. combination which alleviates said deterioration of the insect toxicant consistingofafrom-iabout 30%"to about-80% by weight of aglycolselected from the group, consisting ofethylene glycol, propylene glycol, diethylene glycol ,and

triethylene: glycol; and from about 2.0% to about byi-weight of sodium hydroxide;

2. A stabilized insecticidal composition comprising in combination;heptachlor; a finely divided; solid-' carrien active in deteriorating said insect toxicant mixed therewith selected from the group consisting of kaolin clay, montmorillonite clay, attapulgite clay, diatomaiceous earth and vermiculite; and between 96% and 12% of the carrier of a combination which alleviates said deterioration of the insect toxicant consisting of from about 30% to about 80% by weight of a glycol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, and triethylene glycol; and from about 20% to about 70% by weight of sodium hydroxide.

3. A stabilized insecticidal composition comprising in combination: endrin; a finely divided solid carrier active in deteriorating said insect toxicant mixed therewith selected from the group consisting of kaolin clay, montmorillonite clay, attapulgite clay, diatomaceous earth and vermiculite; and between 16% and 12% by weight of the carrier of a combination which alleviates said deterioration of the insect toxicant consisting of from about 30% to about 80% by weight of a glycol selected from the group consisting of ethylene glycol, propylene glycol, diethylene glycol, and triethylene glycol; and from about 20% to about 70% by weight of sodium hydroxide.

4. A stabilized insecticidal composition comprising in combination: chlordane; a finely divided solid carrier active in deteriorating said insect toxicant mixed therewith selected from the group consisting of kaolin clay, montby weight 1 20% to about 70% by weight of sodium hydroxide.

References Cited in the file of this patent UNITED STATES PATENTS 2,371,644 Petering Mar. 20, 1945 2,407,149 Gardenier Sept. 3, 1946 2,722,557 Danison Nov. 1, 1955 2,768,181 Bellin et a1. Oct. 23, 1956 OTHER REFERENCES 

1. A STABILIZED INSECTICIAL COMPOSITION COMPRISING IN COMBINATION: AN INSECT TOXICANT DERIVED FROM HEXACHLOROCYCLOPENTADIENE SELECTED FROM THE GROUP CONSISTING OF ENDRIN, ISODRIN, ALDRIN, DIELDRIN, CHLORDANE AND HEPTACHLOR; SECT TOXICANT MIXED THEREWITH SELECTED FROM THE GROUP CONSISTING OF KAOLIN CLAY, MONTMORILLONITE CLAY, ATTAPULGITE CLAY, DIATOMACEOUS EARTH AND VERMICULITE; AND BETWEEN 1/2% AND 12% BY WEIGHT OF THE CARRIER OF A COMBINATION WHICH ALLEVIATES SAID DETERIORATION OF THE INSECT TOXICANT CONSISTING OF FROM ABOUT 30% TO ABOUT 80% BY WEIGHT OF A GLYCOL SELECTED FROM THE GROUP CONSISTING OF ETHYLENE GLYCOL, PROPYLENE GLYCOL, DIETHYLENE GLYCOL AND TRIETHYLENE GLYCOL; AND FROM ABOUT 20% TO BOUT 70% BY WEIGHT OF SODIUM HYDRIXIDE. 